The present invention relates to a light-reflecting device which receives light transmitted through a light-guiding cable and which effectively diffuses and radiates the same outwardly.
The present applicant has previously proposed various methods and systems to focus solar rays or artificial light rays by using lenses or the like to guide the focused light rays into a light-guiding cable and to transmit them to wherever the light is needed for illumination or for other purposes, as for example, to supply light energy for the photosynthesis of plants being cultivated in a controlled environment etc.. However, in the case of utilizing light energy for plant cultivation there arises the following problem. When light rays are supplied from the end of a light-guiding cable, they can be radiated only within a small angle of about 46.degree. since a light-guiding cable has a predetermined numerical aperture. Therefore, in such circumstances, desirable light radiation may not be obtained i.e. if the light is directly emitted from the end of the fiber optic cable. In order to solve this problem, the present applicant has also proposed various kinds of light radiators which can effectively diffuse light rays transmitted through a light-guiding cable and which can radiate the same over any desired area.
The present applicant has previously proposed a light-reflecting device comprising a light-guiding cable, a tubular body and a runner. In the tubular body, with at least one transparent side wall, two rails are installed extending in the axial direction thereof as well as a runner which travels along said rails. The runner is composed of wheels for traveling on the rails, a running body mounted on the wheels, a motor mounted on the body for driving the running wheels and a reflecting plate. Light emitted from the light-guide into the tubular body is reflected by the reflecting plate and radiated out of the tubular body through the transparent wall portion. The rails are made of a conductive material and sliders are in contact with these rails respectively. By changing the polarity of the voltage being applied between the rails, the motor is forced to rotate in the reverse direction causing the runner to reciprocate inside the tubular body. The above-mentioned device is able to more effectively diffuse and more widely radiate light emitted from a light-guide cable and its runner is easy to be driven. However, it has the drawback that the intensity of the light radiation is constant and cannot be increased when any object requires more intensive light radiation.